An experimental and theoretical investigation to examine the nonlinear response of small ice masses to a wide range of wave excitations has been conducted. The motion of a free floating spherical model in a regular wave field ranging in length from .61 to 5.6 m and in steepness from 1/100 to 1/10 has been analyzed. Measured heave motions and forces in the direction of surge of a towed model in waves are in good agreement with the theoretical predictions of a time-domain motion simulation program. Therein, forces are calculated by direct integration of pressures over the instantaneous wetted body surface. The scattering forces are estimated by the equivalent motion concept.